This invention relates to an improved assembly of components that collectively are capable of performing several functions including those of a pressure washer and a ground heater.
BACKGROUND OF THE INVENTION
Ground heaters are primarily used to heat frozen ground in preparation for laying concrete. They can also be used to accelerate the curing of concrete in cold weather. For such purposes they usually employ a pump, a heating system for water, a large water tank and a long hose stored on a reel and rely on an outside source of electrical power to operate. The hose is generally spread snake like over the ground or fresh concrete for thawing or curing. In temperate climates ground heaters can be used only during the winter months, usually as little as two months out of a year. Since they generally cost tens of thousands of dollars, they represent a very large investment for something that lays idle for most of the year. U.S. Pat. Nos. 5,964,402 and 6,408,843 disclose and claim an improved portable ground heating equipment or components thereof but do not address the desirability of increasing the versatility and economy of the dedicated equipment tied up in ground heaters.
Similarly pressure washers are primarily used for washing all sorts of surfaces, structures and equipment and, although they often lay idle for long periods of time, their usage is less limited by weather especially if they employ a heating system. The more sophisticated units can employ an engine, a pump, a generator, a heating system, a water tank of some sort and a relatively short hose with a pressure wand.
It is not uncommon for builders to transport and use both ground heaters and pressure washers of some type at the same building site at about the same time for their independent uses.
The present invention resulted from the astute observation that by combining some of the basic components of ground heaters and pressure washers in modified form the capabilities of both ground heaters and pressure washers could be retained and even improved. It was also observed that equipment with the capabilities of pressure washers and ground heaters are often useful to the same people under similar circumstances, especially by builders at building sites. Thus pumps, water and fuel tanks, heating systems and platforms or trailers are common to both. To the extent that the components differ they are compatible and, when optimized and used for both purposes, add to the utility and economy of each component as well as the combination. Thus pressure washers are inter alia useful to (1) wash buildings, cars, trucks, heavy equipment, buildings, decks, and surfaces of all kinds; (2) perform hydrostatic testing; (3) do sand blasting; (4) do water jet drain cleaning; and (5) clean industrial plants. Ground heaters can thaw frozen ground, cure concrete, act as temporary boilers; and, in combination with space heaters, heat buildings and/or rooms.
It is an object of this invention to provide one integrated assembly of components which will inter alia perform all of the functions of a pressure washer and a ground heater more economically, more effectively and more conveniently than the pressure washer and ground heater employed separately. It is also an object of this invention to provide equipment for use by builders on site year-round and not just for the cold two or three months of the year. It is a further object of this invention to make more efficient and extensive use of those parts of pressure washers and ground heaters that are common to both.
The foregoing objectives can be accomplished essentially by the addition of a ground heater hose and reel and a large water tank to the components of a pressure washer equipped with a heating system with sufficient capacity for use in a ground heater and preferably a positive displacement pump. In addition the controls, connections and platform on which the entire assembly is mounted are added in modified form to accommodate all of the functions and components of the resulting pressure washer/ground heater.
The ground heater function generally requires more hose and a correspondingly larger reel to store the hose than the pressure washer. Rather than use the same reel and hose for both pressure washer and ground heater uses, it has proven necessary to provide separate reels and hoses for each type of use. A ground heater hose must be capable of withstanding both the high temperatures required for ground heating and the additional abuse likely to be encountered by hose spread over the ground at a building site where mobile heavy equipment is commonplace and can accidentally run over the hose. Since long lengths of hose are often required for heating large ground areas, a large electrically powered reel is highly desirable to store, extend and retract the hose.
A much shorter hose capable of withstanding high pressures (e.g. 3000 psi compared to 150 psi for a ground heater) on a smaller, manually operated reel is generally acceptable for pressure washer use.
A large water tank is a necessity to fill a long ground heater hose and can be useful on occasion for pressure washer use. Likewise provision must be made in the construction of the combination to allow for the use of the combination for any of the basic uses of ground heaters and pressure washers. Thus the water must be capable of delivery to the ground heater hose separately and alternatively from the pressure washer hose. Although ground heater uses always require heated water containing antifreeze (e.g. propylene glycol), pressure washer uses may or may not employ heated water always without antifreeze. A float tank adapted for connection to an outside source of water is also a useful component for pressure washer use, especially during the winter when the main water tank contains antifreeze which is not suitable for pressure washer use. Special connections are required not only to facilitate separation of the two sources and types of water but also to accommodate the large variation in the pressure with which the water is delivered for the two separate uses.
An ordinary garden hose can be employed to connect the float tank to an outside source of water. The outlet from the float tank is connected to one inlet of a three way valve. The outlet from the main water tank is connected to the other inlet of the three way valve. The outlet from the three way valve is connected to the pump. The operator can thereby connect the pump to either source of water. The pump then forces the water through the water heater, preferably a water tube boiler, to an outlet to which either the ground heater hose or the pressure washer hose can be connected. A manual connection is preferred because presently available commercial valves would have difficulty handling the high pressures (e.g., 3000 psi) often employed for pressure washer use.
It is also highly desirable to splice a safety relief valve in the conduit between the pump and the boiler to prevent the lower pressure hose used for ground heating (e.g. 150 psi) from bursting in the event the ground heater hose is accidentally pinched or constricted. If that should happen the valve would simply prevent the water from reaching the boiler and would instead redirect the water back into the water tank.
The combination can also be modified so that the ground heater hose can be directed to a space heater to heat rooms or buildings at a building site after it has passed through the ground heating hose and before it returns to the storage tank. This increases the usefulness of the combination of the present invention at substantially no additional cost to heat a building or room.
A third small manually operated hose reel can advantageously be added to the combination of this invention to store, extend and retract an ordinary garden hose which can be connected to any outside source of water to fill the large storage tank, especially on site.
Ground heaters often require a separate source of electricity to power their pump and burner reducing their flexibility for use at sites where a power source is not available. The combination of this invention generates its own power and thereby avoids this problem. Since a ground heater is used to thaw frozen ground in winter months, it is necessary to use antifreeze in the water in appropriate concentrations for the temperature conditions encountered. Propylene glycol is the preferred antifreeze, especially since it is biodegradable and therefore environmentally friendly if spillage occurs for any reason.
Although individual components are optimized for combined use, the present invention essentially transforms components normally found in a pressure washer with a heating system into a ground heater/pressure washer by combining standard components of existing ground heaters, primarily ground heater hose and reel and a large water tank, to a modified pressure washer in a novel way on a suitable platform. Additional components and unique connections between the components complete the invention. Although a large holding tank for antifreeze containing water is most preferred for ground heater use, other liquids such as those containing detergents could be employed especially for pressure washer use.